PO-0848: Study of anatomical change during H&N RT with effect on delivered dose to spinal cord, parotid gland

BACKGROUND Establishing the usefulness of adaptive radiotherapy in our setting with limited data might help to ensure better conformity and reduce treatment related morbidity. Hence we conducted this study to elicit the benefit of adaptive radiotherapy with helical tomotherapy. METHODS This is a prospective study conducted among 25 head and neck cancer patients undergoing radiotherapy with helical tomotherapy. All patients underwent initial radiation therapy treatment planning simulation positron emission tomography computed tomography (PET CT/ CT scan) [CT-1], followed by repeat PET CT/ CT scan at 4th - 5th week of radiotherapy [CT-2]. Planning for full intended dose [66 Gy - 70 Gy] was done on both the scans, keeping the radiation therapy planning parameters same. Changes in the volume of the clinical target volumes (CTV), changes in the volume and dose to spinal cord, bilateral parotids, and mandible were compared. A p - value of < 0.05 was considered for statistical significance. RESULTS A significant reduction in the volumes of tumour - CTV-1 [CT-1 v/s CT-2: 166.82 cc v/s. 150.63 cc] and of lymph nodal region - CTV-2 [CT-1 v/s CT-2: 260.29 cc v/s 228.00 cc], contra lateral parotid gland [CT-1 v/s CT-2: 33.00 cc v/s 18.72 cc] were observed (P < 0.05). The mean doses received by contra lateral parotid gland [CT-1 v/s. CT-2: 23.14 Gy v/s 21.26 Gy] were significantly lesser in the CT2 scans (P < 0.05). The mean maximum doses were also significantly lesser to the mandible and spinal cord i.e., CT-1 v/s. CT-2: 68.528 Gy v/s 67.39 Gy and 39.45 Gy v/s. 37.33 Gy respectively (P < 0.05). A significant reduction in standardised uptake value (SUV), values of the primary tumour and involved lymph nodes was observed between CT-1 and CT-2. CONCLUSIONS During 4th to 5th week of radiation therapy, significant reductions in the CTVs and in dose to OARs were noted. Thus, we recommend at least one re-simulation scan and re-planning during radiation therapy, irrespective of the type of technique of radiation therapy. KEYWORDS Adaptive Radiation Therapy, IMRT, Tomotherapy

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SPECT-CT VISUALIZATION OF SENTINEL LYMPH NODES AND LYMPH FLOW FROM TONGUE CANCER

Problems in oncology ◽

10.37469/0507-3758-2019-65-2-250-255 ◽

2019 ◽

Vol 65 (2) ◽

pp. 250-255

Author(s):

Sergey Kanaev ◽

Sergey Novikov ◽

Pavel Krzhivitskiy ◽

Zamira Radzhabova ◽

Maksim Kotov ◽

...

Keyword(s):

Spinal Cord ◽

Parotid Gland ◽

Lymph Nodes ◽

Treatment Planning ◽

Tongue Cancer ◽

Primary Tumour ◽

Sentinel Lymph Nodes ◽

Lymph Flow ◽

Radiotherapy Planning ◽

Radiation Fields

The main purpose of the study was to determine distribution of sentinel lymph nodes in patients with tongue cancer. SPECT-CT visualization of sentinel lymph nodes was performed in 19 primary patients with clinically T1-2N0M0 tongue cancer. SPECT-CT acquisition started 60-120 min after peritumoral injections of 99mTc-nannocolloids (100-150MBq in 0.3-0.4ml). Finally we analyzed lymph flow patterns and localization of lymph nodes with radiocolloids uptake. Bilateral lymph flow from the tongue cancer was detected in 9 (47%) of 19 patients. In 6 cases bilateral pattern was associated with tumors less than 5mm from medial sulcus of the tongue. On the contrary, in 9 of 10 patients with lesions more than 4mm from medial sulcus we detected monolateral lymph-flow. In 4 (21%) of 19 patients SPECT-CT visualized sentinel lymph nodes only in groups Ib-IIa. Modeling of radiotherapy with with standard and lymph-flow guided radiation fields was performed on Eclips treatment planning station. It demonstrated that with lymph-flow guided strategy irradiated volumes can be reduced from 1224 cm3 to 367 cm3, dose to spinal cord can be reduced from 24,7Gy to 14.3Gy, medial dose to contralateral parotid gland - from 24,6Gy to 12,4 Gy. SPECT-CT with radiocolloids can be successfully used for visualization of lymph flow from the primary tumour and subsequent radiotherapy planning.

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Adaptive Planning of Intensity Modulated Radiation Therapy for Head-and-Neck Cancers for Improved Accuracy of Delivered Dose in Patients With Clinically Significant Anatomical Change Due to Therapy

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2012.07.1267 ◽

2012 ◽

Vol 84 (3) ◽

pp. S478

Author(s):

M. Bishop ◽

A. Al-Basheer ◽

J. Greskovich

Keyword(s):

Radiation Therapy ◽

Head And Neck ◽

Intensity Modulated Radiation Therapy ◽

Head And Neck Cancers ◽

Adaptive Planning ◽

Intensity Modulated ◽

Anatomical Change ◽

Clinically Significant ◽

Improved Accuracy ◽

Delivered Dose

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Daily MVCT to Evaluate the True Delivered Dose to the Spinal Cord, Mandible, and Parotid Glands during the Head and Neck Cancer Radiotherapy

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2009.07.1500 ◽

2009 ◽

Vol 75 (3) ◽

pp. S657

Author(s):

J. Cui ◽

B. Li ◽

H. Golding ◽

J.A. Purdy ◽

A.M. Chen

Keyword(s):

Spinal Cord ◽

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Parotid Glands ◽

Cancer Radiotherapy ◽

Delivered Dose

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MRI findings of epithelial–myoepithelial carcinoma of the parotid gland with radiologic–pathologic correlation

Japanese Journal of Radiology ◽

10.1007/s11604-021-01243-0 ◽

2022 ◽

Author(s):

Taketo Suto ◽

Hiroki Kato ◽

Masaya Kawaguchi ◽

Kazuhiro Kobayashi ◽

Tatsuhiko Miyazaki ◽

...

Keyword(s):

Spinal Cord ◽

Parotid Gland ◽

Myoepithelial Carcinoma ◽

Mri Findings ◽

Apparent Diffusion Coefficient Value ◽

Adjacent Structures ◽

Apparent Diffusion ◽

The Mean ◽

Epithelial Myoepithelial Carcinoma ◽

Solid Lesions

Abstract Purpose This study aimed to describe the MRI findings of epithelial-myoepithelial carcinoma (EMC) of the parotid gland. Materials and methods Seven patients (four males and three females) aged 40–86 years (mean age, 64 years) with histologically proven EMC of the parotid gland who underwent surgical resection after preoperative MRI were enrolled. MRI images were retrospectively reviewed and contrasted with pathological findings. Results Five patients (71%) had predominantly solid lesions, and two (29%) had predominantly cystic lesions. All seven lesions had well-demarcated margins and capsules without the invasion of adjacent structures. The capsules were incomplete in five lesions (71%) and complete in two (29%). Four lesions (57%) exhibited a multinodular structure with internal septa. Cystic components were observed in three lesions (43%). On T1-weighted images, the solid components were frequently homogeneous (5/7, 71%), and demonstrated isointensity in five lesions (71%) and hypointensity in two (29%) relative to the spinal cord. On T2-weighted images, the solid components were usually heterogeneous (6/7, 86%), and demonstrated hyperintensity in five lesions (71%) and isointensity in two (29%) relative to the spinal cord. The mean apparent diffusion coefficient value of the solid components was 0.967 × 10−3 mm2/s. Conclusion Parotid gland EMCs usually appeared as predominantly solid lesions with well-demarcated margins and capsules. A multinodular structure with internal septa was characteristics of EMCs.

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